A Dilatometric Study of the Influence of Residual Iron Content on the Annealing Behavior of Cartridge Brass

Solid solutions alloys may have their annealing behavior affected by solute concentration. Mathematical models assume complex equations with parameters of hard and tedious assessment making empirical tests rather necessary. This work evaluated the residual iron content (from ~100 ppm to ~600 ppm) influence on annealing of a cartridge brass. Dilatometry results showed an anomaly expansion peak on the onset of recrystallization. However, at the end of the annealing process the samples underwent a contraction of 4.68-7.51x10^-4, comparable with literature. The residual iron content had no influence on recrystallization behavior of the samples, although solute drag effect clearly slowed down grain growth at 600 ppm Fe concentration, especially when annealing happens up to 500ºC. The dilatometric variations between the samples and the anomaly expansion peak during recrystallization were considered as resulting from grain growth of recrystallized nanosized grains and/or from second phase transformations. New tests are proposed to elucidate the phenomena behind observations.

Keywords:
Recrystallization; Growth; dilatometry; Brass